Method and apparatus for handling of a fluid



Jan. 28, 1969 L. W. POLLOCK METHOD AND APPARATUS FOR HANDLING OF A FLUID 19 l COOLANT OUT COOLANT IN q COOLANT IN) Filed April 16, 1963 TO POLMERJ RECOVERY CATALYST] SOLVENT] BUTADIENE FEED INVENTOR.

L.W. FOLLOCK COOLANT ouT United States Patent 3,424,733 METHOD AND APPARATUS FOR HANDLHQG 0F A FLUID Lyle W. Pollock, Bartlesville, Okla, assignor t0 Phillips Petroleum Company, a corporation of Delaware Filed Apr. 16, 1963, Ser. No. 273,391 US. Cl. 260--85.3 6 Claims Int. Cl. C08f 1/98; C08f 1/06 This invention relates to a method and apparatus for the handling of a fluid. In one of its aspects, it relates to a method for admixing or agitating a fluid, or fluids, to provide efiicient heat transfer and mixing by conducting said fluid or fluids in a predetermined pathway in a zone, the fluid following a course of flow along the axis of said zone, from the flow along the axis of said zone substantially perpendicularly with respect to said axis into and then along or through an annulus in said zone, then across and into, and along or through a further annulus in said zone, the fluid being removed peripherally from a locus approximately at the end of its flow along or through said last annulus, the annuli being centered on the axis of said zone, and agitation of the fluid in said annuli being effected by rotating an axially-centered cylindrical open-ended agitator element in said fluid, said cylindrical agitator, in part, forming, and, in part, defining, said annuli, as more fully described herein. In another of its aspects, the invention relates to a method, as described, the flow being in direction opposite to that just stated.

In another of its aspects, the invention relates to an apparatus correlated with and permitting the execution of the method of the invention, the apparatus comprising, in combination, means to contain a first fluid, a rotatable cylindrical agitator closed at one end extending from one end of said first means axially a substantial distance in said first means but not completely to the other end of said first means and positioned axially in said first means, means coacting with said agitator to rotate the same, means for feeding said first fluid axially into said means to contain a first fluid into the closed end of said agitator, and means for recovering said first fluid from the apparatus at .the outer periphery thereof, in a preferred embodiment, said last-mentioned means being at that end portion of the apparatus at which the closed end of the agitator is located.

In another of its aspects, the invention relates to an apparatus correlated with and permitting the execution of the method of the invention, the apparatus comprising, in combination, means to contain a first fluid, means at least in part surrounding said means adapted to contain a heat exchange fluid to adjust the temperature of said first fluid in said first means, a rotatable cylindrical agitator closed at one end extending from one end of said first means axially a substantial distance in said first means but not completely to the other end of said first means and positioned axially in said first means, means coacting with said agitator to rotate the same, means for containing a heat exchange fluid to adjust the temperature of said first fluid extending from said other end of said first means axially into said agitator toward, but not completely to the closed end of said agitator, a means for feeding a heat exchange fluid into each of said means for containing the heat exchange fluid to adjust the temperature of said first fluid, means for feeding said first fluid axially into said means to contain a first fluid through, but out of contact with, heat exchange fluid in the last-mentioned means for containing a heat exchange fluid, into the closed end of said agitator, and means for recovering said first fluid from the apparatus at the outer periphery thereof, in a preferred embodiment, said lastmentioned means being at that end portion of the apparatus at which the closed end of the agitator is located.

3,424,733 Patented Jan. 28, 1969 In a further aspect of the invention, it provides method and means especially suited to the conducting of certain chemical reactions, for example, solution, emulsion or suspension polymerization processes, for example, the production of polybutadiene, polyethylene, polypropylene, butadiene-styrene copolymer, polyisoprene, carboxytelechelic polybutadiene, and many other processes including polymerization of other compounds, the interpolymerization of other compounds or materials, as well as chemical reactions other than polymerization, for example, condensation reactions, reactions involving hydrolysis, etc., the reactions or operations to which the invention can be applied being of the type wherein good mixing and/or good heat exchange to maintain uniform temperatures or heat distribution are essential to best or optimum operation, especially operations which desirably are to be elfected in a short or reduced time. Thus, in a still further aspect, the invention additionally provides method and means for increasing rates of reaction in those reactions wherein diffusion rates limit reaction rates. At the same time, the invention provides for flow of reactants through the entire two-annulus reaction zone with little or no back-mixing or short-circuiting, thus contributing to higher and more uniform reaction rates than can be obtained in the conventional stirred pot reactor, i.e., channeling or dis-uniform flow of reactants through the reaction is very substantially reduced if not entirely completely eliminated.

It has been found that for viscous, shear-sensitive solutions, such as solutions involved in the production of cispolybutadiene, it is diflicult to obtain effective agitation with conventional type mixers. The polymerization of butadiene to cis-polybutadiene rubber releases about 600 B.t.u per pound of polymer produced. Thus, a reactor for this type of process must provide effective mixing and heat transfer and distribution to maintain adequate heat transfer rates and also to prevent stagnation. Stagnation will cause problems in control of product quality as well as producing other operating problems. With the efiicient heat transfer and uniform mixing of the flowing stream in the reactor of the present invention, it is possible in such type of reaction to dispense often with coolants in the heat exchange zones, described herein, or in at least one of them.

In a further aspect still, the invention relates to a method and apparatus correlated therewith in which a fluid to be treated, reacted or agitated is fed axially into and from the open end of a rotatable cylindrical agitator substantially throughout the length of the agitator to the closed end of said agitator and there released into said closed end at a substantially axially disposed locus, then passed from said locus, annularly of the axial feed, back to the open end of said agitator, around said end, and then annularly of said agitator to the outside thereof to an upper part of a zone containing said agitator and there removed from said zone. In lieu of first feeding into the axial locus, as described, the invention can be conducted by reversing the flow as by feeding to the outside of the closed end of the agitator, along the same, and then into its open end towards and to its closed end and then removing the reaction mass from the apparatus from said closed end, as by a pipe extending into said agitator and about to the closed end thereof.

I have now conceived a method and have conceived a design of an apparatus for the handling of fluids, especially viscous materials, which will provide complete thorough mixing and high heat transfer rates. The method involves introducing into a reaction zone the fluid to be treated, which can be undergoing treatment or reaction as introduced (through an axially disposed inlet zone), into or toward the closed end of a cylindrical agitator surrounding the axially disposed inlet zone and providing an annulus therebetween and the cylinder, and then passing said fluid into said annulus and from said annulus around the open end of the cylinder through a further annulus formed between the boundary of the reaction zone and the cylinder therein, and finally from the periphery of said reaction zone, as will appear more fully below.

The axially disposed inlet zone and the reaction zone can each be provided with a heat exchange zone and the temperature of each zone can be adjusted therewith.

Thus, the method when a heat exchange zone is employed involves axially introducing into a reaction zone the fluid to be treated, which can be undergoing treatment or reaction as introduced, surrounded by a heat exchange zone into or toward the closed end of a cylindrical agitator axially surrounding the heat exchange zone and providing an annulus therebetween and the cylinder, and then passing said fluid into said annulus and from said annulus around the open end of the cylinder through a further annulus formed between the boundary of the reaction zone and the cylinder therein, and finally from the periphery of said reaction zone, and surrounding said reaction zone with a heat exchange zone and adjusting the temperature of the reaction zone therewith, as will appear more fully below.

The conceived design for an apparatus suited to eflect the methods of the invention and which is correlated with said methods, in one embodiment, suited to the operation of the several methods herein disclosed, comprises, briefly, a substantially cylindrical upright reaction vessel, a downwardly-depending rotatable stirring cylinder closed at its upper end and in metal-to-metal contact with said vessel only at its upper end by means of a shaft from which it depends, an internal annular heat-exchange container into which a heat-exchange medium can be passed and from which the heat-exchange medium can be removed while fluid to be treated can be passed therethrough out of contact with said heat-exchange fluid, said last container extending upwardly axially into said stirrer, said stirrer defining an annulus between said last-mentioned container and itself, and a further annulus between itself and the upright vessel, the upright vessel being surrounded by a jacket through which heat-exchange medium can also be circulated. A motor or other means is employed to rotate the stirrer or cylinder which provides the required stirring to effect good contact.

Correlations involved and calculations to be made in the general construction of a specific embodiment of the apparatus of this invention will be aided by a study of Modern Developments in Fluid Mechanics, Volume 2, Oxford Press, page 385. Sufiice to say, now, that one skilled in the art in possession of this disclosure and information available in the prior art will readily be enabled to design an apparatus according to the invention here set forth. He will understand that when a chemical reaction results in a solution, emulsion, slurry or other multiphase mixture having non-Newtonian viscosity characteristics, the problems of proper heat removal and mass transfer become important for the maintenance of reaction and production rates and product properties. Particularly when the reaction mass becomes pseudo-plastic in a. conventional reactor, consisting of a cylindrical vessel with helical or vertical coils, baflles, and one or more mixing impellers, in the neighborhood of the coils or baflles, where shear rate is low, effective viscosity becomes high and resultant heat-transfer coefficients and diffusion rates become low. Usually when there is a definite limit to the amount of cooling surface available, better mixing and more turbulence are commonly resorted to in order to increase, as much as possible, the film coefficient. However, much improvement remains to be desired.

A purpose of this invention is to provide a method for the handling of a fluid. Another purpose of this invention is to provide an apparatus for the handling of a fluid. A

further purpose still is to provide a method of handling a fluid during its treatment or reaction in which improved heat transfer and/or mass transfer and/ or reaction rates can be accomplished, particularly when the fluid tends to become viscous or to have stagnant or relatively stagnant areas therein. It is a further purpose of the invention to provide a method and an apparatus wherein various polymeric or modified polymeric products or copolymers or modified copolymers can be produced. It is a still further purpose of the invention to provide an improved method and apparatus for the production of polybutadienes, polyethylenes, polypropylenes, butadiene-styrene co polymers, polyisoprenes, carboxy-telechelic polybutadienes, and other polymers or other products in the production of which viscous or relatively stagnant areas in the reaction zone occur. It is a still further purpose of the invention to provide an improved design and apparatus for the production of eddy turbulence mixing while effectively introducing into, conducting through, and removing from a reaction vessel, a reacting fluid, or a fluid being treated, while at the same time providing for said fluid effective indirect heat exchange between separated flowing portions thereof and/or effective amounts of heatexchange medium effecting indirect heat exchange with said fluid. A still further purpose of the present invention is to provide a novel and improved agitating method and/ or an apparatus wherein symmetrical eddy patterns can be formed in annular sections of a zone or vessel employing an essentially cylindrical agitator which needs be suspended or mounted, at but one end thereof, or at only one point of a vessel containing the same and in which it, at least in part, forms several annuli, and wherein indirect heat transfer can be effected between the contents of adjacent annuli.

Other aspects, objects and the several advantages of this invention are apparent from a study of this disclosure, the drawing, and the appended claims.

According to the present invention, there is provided a method for agitating a fluid and effecting improved heat and mass transfer which comprises providing:

(a) a treating zone;

(b) an indirectly heat exchanging temperature control zone surrounding said treating zone;

(c) an indirectly heat exchanging temperature control zone axially disposed in said zone, extending substantially into said zone from one end thereof and terminating at a substantial distance from the other end thereof and spaced from the side of said treating zone parallel to the axis of said treating zone, thus providing an annulus;

(d) a rotating axially disposed cylindrical agitator, closed at one end, in said treating zone extending from said treating zone extending from said other end of said treating zone substantially toward said one end of said treating zone and terminating at a substantial distance from said one end of said treating zone, said closed end being at said other end of said treating zone, said cylinder substantially encompassing the axially disposed temperature control zone and, in part, by a division of said annulus, forming and defining with said axially disposed temperature control zone and with said side parallel to the axis of said treating zone two annuli communicating with each other around the end of the wall of said cylinder at its open end;

(e) a substantially axial inlet for fluid, through said axially disposed temperature control zone, into the closed end of said rotating cylinder;

(f) a treated fluid outlet from said treating zone approximately at said other end thereof;

(g) then passing a temperature control medium through each of said temperature control zones;

(h) then passing a fluid through said axial inlet and said axially disposed temperature control zone into the closed end of said rotating cylinder;

(i) then passing said fluid through the annulus between said rotating cylinder and said axially disposed temperature control zone;

(j) then passing said fluid through the annulus between said cylinder and said treating zone; and

(k) then removing the thus-agitated and treated fluid from said treating zone through said outlet.

It is to be understood that the invention can be practiced without the use of, or without the passage of a temperature control medium through, one or both of said temperature control zones.

Also, according to the invention, there is provided an apparatus, as described herein, the essential characteristics of which are that it provides a rotatable cylindrical agitator means closed at one end thereof disposed in a containing vessel and encompassing an axial inlet means through which a feed to be treated and agitated while treated is passed into the closed end of the cylinder, then between the cylinder wall and said encompassed axial inlet means, and then between the wall of the vessel and the cylinder and then from the Vessel the inlet means being encompassed by a heat exchange means. Further, the vessel can be surrounded by heat exchange means.

Thus, also according to the invention, there is provided an apparatus, as described herein, the essential characteristics of which are that it provides a rotatable cylindrical agitator means closed at one end thereof disposed in 3. containing vessel and encompassing a heat exchange zone through which a feed to be treated and agitated while treated for efiicient heat transfer is passed into the closed end of the cylinder, then between the cylinder wall and said encompassed heat exchange means, and then between the wall of the vessel and the cylinder and then from the vessel, the vessel being surrounded by heat exchange means.

Referring now to the drawing which will be described in connection with the solution polymerization of butadiene in the presence of a catalyst, butadiene fed by 1 and solvent toluene fed by 2 and catalyst, titanium tetrachloride-triisobutyl aluminum and iodine fed by 3, are passed by 4, into axially-disposed section 5' of treating zone or vessel 6, which is surrounded by heat exchange jacket or section 7. Axial zone 5 is formed within and extends throughout the length of axially-disposed heat exchange zone or section 8 into which a coolant is passed by 9 and from which used coolant emerges at 10. The reaction mixture in zone 5 is quite fluid and enters into section 11 formed by the closed end of rotating cylinder 12 and the outer walls of heat exchange section 8 at its upper end. The reacting mixture now commences to receive agitation from rotating cylinder 12 which is driven by motor 13 connected thereto by shaft 14. The reacting mixture passes downwardly through annulus 15 and at the bottom end of the cylinder wall passes into, and moves upwardly through, annulus 16 and from vessel 6 by outlet 17. A coolant passes into the peripheral jacket 7 by inlet 18 and is removed from 7 by outlet 19. It will be noted that heat transfer can take place between the contents of annulus 15 and those of annulus 16, through the wall of cylinder 12.

In any particular embodiment, as noted, only one, or both, or neither of the heat exchange zones will be used. Also, one zone can be a heating zone while another is a cooling zone, depending upon the treatment for which the apparatus is being employed.

The several radial measurements, R R and R indicated on the drawing, are generally selected properly to cause the eddy turbulences between the walls of the annuli to be approximately equal. Or, if desired, the turbulence conditions in one annulus can be more severe than in other in order to compensate for the increase in viscosity which occurs during the reaction here described. Additional agitation can also be provided in the annuli by known prior art methods. One skilled in the art in possession of this disclosure, having studied the same, will understand that various correlated factors are involved in the selection of proper dimensions, rotational speeds and turbulence at any particular point in respect of the amount of heat desired to be transferred, etc.

The application of the type reactor here described will provide the effect of many reactor vessels in a reaction train because, as the eddies develop in the annuli, the turbulence is confined to each eddy with little transfer of mass from the space occupied by one eddy to the space occupied by another. In a continuous system, the transfer between eddies will be about equal to the net flow through the reactor. Thus, the flow characteristics of this reactor may be described as essentially pipeline or plug type flow, modified by localized eddy turbulence to promote local but not general mixing and/or heat transfer.

The reactor here described allows effective handling of a much higher concentration of polymer or product in the efiiuent than normally possible with a conventional reactor system, as one skilled in the art in possession of this disclosure, having studied the same, will understand. This advantage from the use of the type of reactor here described to carry out a method as herein described, which involves use of a solvent, permits reduction of the solvent-recovery equipment normally required, and thereby will reduce investment, as well as operating costs of a commercial plant. In addition, where diffusion rates are controlling, higher reaction rates may be realized, thus benefits are gained via conversion increase at fixed feed rate, increased feed rate at fixed conversion or some combination thereof. The net effect is to increase the reactions productive capacity.

Thus, there is provided and applied a method and apparatus involving a reactor system for viscous materials permitting complete thorough mixing and, therefore, high heat transfer rate, as described.

The following example is provided for disclosure purposes. Variations and modification can be accomplished therein, as one skilled in the art will understand.

Example A feed stream containing 1000 parts by weight of nhexane and parts by weight of butadiene is pre-mixed in a stirred vessel and introduced into a reactor like that shown in the drawing, together with 0.15 part of butyl lithium, at a temperature of F. The cup-shaped cylindrical agitator is rotated at a speed of 787 r.p.m. The capacity of the reactor is 2.2 gallons and the residence time of the reactants in the reaction zone is five minutes. The reactor effluent is withdrawn at a temperature of about 240 F. Conversion of 92 percent of the butadiene to a rubbery polymer is obtained at a reaction rate which is approximately seven to eight times that obtained in a stirred pot reactor, i.e., the time during which the reactants are in the reaction is very greatly reduced. Here it is desired that the reaction temperature rise as the reaction progresses, so as to maintain high polymerization rates, but not to exceed 25 0 F. to minimize gel formation. Approximately one-fourth of the heat of polymerization is removed from the reactor, the remainder manifesting itself as sensible heat increase from 165 to 240 F.

In practice of the invention, it will be found that residence times can be reduced to as little as one fifth or even one-tenth the time taken in the conventional stirred reactor.

It is evident fnom a study of this disclosure and the drawing that the rotating cylinder or agitator which is used is mounted at only one end thereof, permitting the serpentine flow from the axis into the intermediate annulus, and from the intermediate annulus, to the outer annulus, and from the outer annulus by way of outlet 17 to product recovery. This type of mounting, whether from above or below, or other point, taken together with the rectilinear character of the preferred agitator which is cylindrical in character, and the disposition of the heatexchanging sections is a feature of the present invention and distinguishes it over priorly proposed mixing apparatus. The flexibility of operation by selection of the proper or desired radii with respect to rate of flow, temperature control desired, and viscosity at any given point, will be obvious to one skilled in the art having read this disclosure and considered its substance.

The axial feed, as in section of the drawing, is another important feature of the invention which, of course, is permited to be obtained or attained by the manner in which the rotating agitator is suspended or supported at only one point. Clearly, were the agitator not open at one end and supported or suspended or mounted at the other end, it would not be possible to axially enter the feed -to the vessel. By axially feeding the reactants, at a time when reaction is occuring, through a carefully-controlled heat exchange section symmetrically disposed in vessel 6, it is possible to obtain very accurate initiation and reaction control by control of temperature and rate of flow.

As a further feature of the invention, the length of shaft 14 and the disposition of the closed end of the cylinder 12 with respect to the top of vessel 6 and the top of section 8 permit variation in the rate of reaction and in the mixing and heat transfer occuring as the fluid passes from section 5 to section and from section 16 to the top of the vessel where the reaction mixture is withdrawn. Thus, although outlet 17 is shown in the drawin as being a side \outlet, it is a feature of the design of the invention that the product can be withdrawn or removed from vessel 6 from an upper or top locus. Indeed, one or more points of removal of reacted mass disposed along the top of the vessel, as shown at 20, can be pnovided and utilized. For completely symmetrical operation, a group of outlets 20 can be disposed peripherally surrounding the packing gland which surrounds shaft 14.

One skilled in the art will understand that both exothermic and endothermic reactions can be conducted according to the method and correlated apparatus of the pre ent invention. Furthermore, the heat exchange section 7 can be extended to substantially completely surround vessel 6 and even cover the top thereof. The thickness of sections 8 and 7 can be varied. For example, section 7 can be thicker at any location desired as dictated by the thermal requirements of the process. The diameter of section 8 can also be varied, as can the diameter of inlet conduit 5.

Since heat transfer zone 7 and 8 are independent, as earlier indicated, considerable flexibility is imparted to this reaction-heat transfer method and apparatus of the invention. Different coolants (or heatants) may be supplied to the two zones, that is, often heat input is required to initiate an exothermic reaction, after which removal of heat of reaction is necessary to provide reaction temperature control, prevent runaway of the reaction and/ or insure the production of material of desired characteristics. Wide latitude is available in choice of heat exchange medium and its thermal capacity, that is, multiple phase operation (vaporiation-condensation, meltingfreezin-g) is possible as well as single phase (temperature change) operation as the mechanism of heat transfer.

Further, some chemical reactions are preferably carried out adiabatioally (no heat addition or removal after initiation), or thermally between the adiabatic and the isothermal states, and it may be readily appreciated that these modes of operation are also readily available. Particularly in the case of polymerizati ons in a solvent medium, where the increasing concentration of product causes increase in rhelogical properties (viscosity et al.) which reduce heat transfer and :mixing effectiveness, and where diminishing concentrations of reactants lower reaction rates (lengthening the time required to reach a desired conversion), is this inventive method and apparatus of great value and applicability.

Also, it may be observed that, depending upon the materials of construction of the inverted-cup stirrer 12, heat may be transferred between the material in annulus 16 and that in annulus 15 thru the wall of stirrer 12, so that the temperature gradient normally associated with a conventional pipeline type of adiabatic reactor may be modified as desired.

In some instances, it may be desirable to provide insulation against heat flow in at least a portion of one or both of the heat exchange zones or sections.

With respect to the foregoing discussion and consideration of the several limitations of the claims which follow in this disclosure, the arrangement of the invention provides a stable rotating cylinder which is well-balanced by equal hydraulic forces on the outside and inside of the cylinder. A longer flow path is provided for a given vessel height. The least power requirements for a given level of turbulence are within easy attainment. Greater heat transfer surface for a given size vessel can be arranged. As indicated, no bearing opposite the end at which the cylinder is mounted is required. In the now-preferred embodiment in which the shaft suspends the rotating agitator, no foot bearing is required.

As earlier noted, but now more fully described, in an important embodiment of the invention, there is provided a method of operation in which the fluid to be treated, reacted, or agitated is fed axially into and from the open end of a rotatable, cylindrical agitator substantially throughout the length of the agitator to the closed end of said agitator and there released into, and at a substantially axially disposed locus, then passed from said locus, annularly of the axial feed, back to the open end of said agitator, around said end, and then annularly of said agitator to the outside thereof to an upper part of a zone containing said agitator and there removed from said Zone. Thus, it is within the contemplation of the present disclosure, in some cases where this is desired, to eliminate section 8 and to replace it with a pipe from which the feed is discharged substantially just below the end of shaft 14. In such event, annulus 15 will extend from just outside the pipe to the Wall of agitator 12. With such a method and correlated apparatus, symmetrical eddy patterns can be formed in annular sections of a Zone or vessel employing an essentially cylindrical agitator which need be suspended or mounted but at one end thereof or at only one point of the vessel containing the same and in which vessel it, at least in part, forms several annuli. The modification or feature of the inventions here discussed can be viewed as a reduction of the radius of section 8 of the drawing to be substantially the thickness of the pipe which would provide section 5. Corresponding adjustment of the other radii would, of course, be properly made.

In the reactor of the invention, the square-eddy mixing in viscous systems, accomplished as it is using a one-end or top-'bearinged hollow cylinder extending downwardly into a reactor vessel over a concentrically disposed feeding or heat exchange structure, involving concentric or axial feed into the closed end of the cylindrical rotating mixer and flow down through annulus between the heatexchanger surface, or feed pipe, on the one-hand, and cylinder wall on the other, around the bottom end of the cylinder upwardly through the annulus between cylinder and reactor wall to the top of the reactor, and from the top to discharge, permits best heat transfer and longest path of travel for a given height of reactor, as noted. A simple calculation indicates that with such arrangement, a total cooling surface of approximately square feet can easily be achieved in such a coannular reactor having a capacity of 150 gallons. Available data in the literature on the heat transfer characteristics of such a coannular system indicates that for a cp. viscosity system with 40 pounds per cubic foot density, 1.5 feet internal diameter, and 2.5 feet outside diameter, and 6.36 feet high (amounting to gallons), the r.p.m. to exceed the critical Reynolds numbers for the formation of secondary flow eddies would be about 34 r.p.m. Among literature references which are aavilable to one skilled in the art,

there may be mentioned Heat Transfer Characteristics of the Rotational and Axial Flow Between Concentric Cylinders, Carl Gazeley, ASME 56-A-128, Lyle Clark, Ph.D. Thesis, University of Michigan, and The Stability of Viscous Fluid Flow Between Rotating Cylinders, S. Goldstein, Cambridge Philosophical Society, vol. 33, 1937, pp. 41-61.

The present invention presents a variety of interesting advantages when applied to polymerization processes now known to the art. Further, it can be employed to blend solutions of materials such as polymers or viscous liquids, especially when such liquids or polymers require some heat to initiate or to effect the blending operation. The invention has considerable potential in semi-adiabatic polymerization reactions for the production of solution polymers known in the art. High solids rubber and plastics processes can be effected according to the method and/or the apparatus of the invention.

A process for the production of cis-polybutadiene which is now practiced in the art is set forth in French Patent 1,247,307. Additional processes which can be conducted according to the method and/ or apparatus of this invention are found set forth in Ser. No. 161,411, filed Dec. 22, 1961, and Ser. No. 117,238, filed June 14, 1961.

While the invention can be applied broadly to the control of reactions wherein a component is only partially converted to the end product, it is of special importance in the control of polymerization reactions, for example, in the catalytic polymerization of olefins and/or diolefins. A process which can be conducted according to the invention is the catalytic polymerization of l-olefins to normally solid polyolefins or polymers, as described in US. Patent 2,825,721 to J. P. Hogan and R. L. Banks, issued Mar. 4, 1958. The invention is also especially useful in the catalytic polymerization of conjugated dienes containing from 4-8 carbon atoms to produce rubbery polymers. Examples of these conjugated dienes include 1,3- butadiene, isoprene, piperylene, 2-methy1-1,3-pentadiene, and the like. These monomers can be reacted to form homopolymers, or copolymerized with each other or with other monomers containing a vinylidene group, such as aliphatic l-olefins containing up to 8 carbon atoms per molecule, styrene, various alkyl styrenes and heterocyclic nitrogen-containing monomers such as 2-methyl-5-vinyl pyridine, and the like.

Catalyst systems which are preferably used in connection with the polymerization of the above-named conjugated dienes are those which contain as an essential component a compound selected from the group consisting of organometals or metal hydrides, the metals being of Groups I, II or III of the periodic table. I prefer to use catalyst systems which comprise (a) a hydride or organo compound of one of the metals aluminum, gallium, indium, thallium and beryllium and (b) a di-, tri-, or tetrahalide of a Group IV metal such as titanium, silicon, thorium, zirconium, tin, lead, hafnium, germanium or cerium. Among the catalyst compositions which I prefer are mixtures of titanium tetrachloride and triethylaluminum, a mixture of titanium tetrachloride and tripropylaluminum, a mixture of titanium tetrachloride and triisobutylaluminum, and a mixture of zirconium tetrachloride and triethylaluminum. A third component can be used if desired. For example, a catalyst containing triisobutylaluminum, titanium tetrachloride and iodine can be used to polymerize 1,3-butadiene to a polymer of high ciscontent. Mixtures of triisobutylaluminum, titanium tetrachloride and titanium tetraiodide can also be used for this purpose.

In such catalyst systems, the mol ratio of the organo' aluminum compound to the titanium tetrachloride is generally in the range from 2:1 to 100:1. The catalyst level in the polymerization should be above about 1.0 gram millimoles of organoaluminum compound per 100 grams of 1,3-butadiene and ordinarily the catalyst level does not exceed about 20 gram millimoles of the organoaluminum compound per grams of 1,3-butadiene.

The temperature of the polymerization should not exceed 300 F. and ordinarily it is within the range of about 60 to F. In the formation of cis-1,4-polybutadiene, a temperature of about 10 to 50 is preferred. In addition, polymerization initiations containing one or several atoms of alkali metal (such as lithium) per molecule are very useful, particularly in the polymerization of dienes such as isoprene, butadiene, et al.,'in cooperation with instant method and apparatus.

The reactions to which the features of my invention are applied are preferably carried out in the presence of a diluent or solvent. The polymerization reactions are ordinarily carried out in the presence of an inert hydrocarbon diluent and monomer and the pressure is sufficient to maintain this diluent and monomer in the liquid phase. Suitable diluents for these polymerization processes are the parafiins and cycloparaffins and/ or aromatic hydrocarbons which are relatively inert, non-deleterious and liquid under the conditions of the process. Low molecular weight paraffins having 3-5 carbon atoms can be used when the process is carried out at low temperatures but the higher molecular weight paraflins and cycloparafiins such as isooctane, cyclohexane and methyl cyclohexane, and aromatic diluents such as benzene, tolune, and the like, are preferred. The reactor residence time can vary widely, for example, from a few minutes to 1 or more hours, for continuous reactions.

The degree of conversion of monomer to polymer depends on the activity of catalyst and upon the temperature of reaction. As stated previously, a preferred operating temperature for the polymerization of 1,3-butadiene is in the range of about 10 to 50 F. With the use of the present invention, conversion, which ordinarily cannot be carried beyond 60 percent and reactor effluent polymer concentration which ordinarily cannot be carried beyond 10 percent, in prior art equipment because of heat removal, mixing and excessive viscosity imposed limitations, can be considerably increased, as indicated elsewhere in this disclosure. This is due to the more efficient heat transfer obtained due to the more efficient agitation involved.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, the drawing and the appended claims to the invention, the essence of which is that there has been provided a method and a correlated apparatus for effecting the method wherein efficient heat and mass transfer can be obtained, even with viscous fluids, by passing these axially into a heat exchange zone in which the fluids are agitated by a cylindrical or equivalent rotating agitator, creating eddies, and passed, step-wise, toward the perimeter of said zone while at the same time traversing the length of said zone, in a preferred embodiment, at least about two times substantialy from end-to-end while contained in annuli, at least in part formed by a central or axial feed or axial heat exchange section, the rotating agitator, and an external wall of said heat exchanger, which can be a heatexchanging wall, substantially as set forth and described.

I claim:

1. In a polymerization process, the improved method for agitating in a unitary operation a viscous, shear-sensiti-ve fluid reacting mass, and effecting improved heat transfer which comprises providing:

(a) a treating zone; I

(b) an indirectly heat exchanging temperature control zone surrounding said treating zone;

(c) an indirectly heat exchanging temperature control zone axially disposed in said treating zone, extending substantially into said treating zone from one end thereof and terminating at a substantial distance from the other end there-of and spaced from the side of said treating zone parallel to the axis of said treating zone, thus providing an annulus;

(d) a rotating axially disposed cylindrical agitator closed at one end, in said treating zone extending from said other end of said treating zone substantially toward said one end of said treating zone and terminating at a substantial distance from said one 12 ous flow pattern through said axial inlet into the closed end of said cylinder, in said closed end of said cylinder radially into and then through said annuli and from said treating zone through said treated fluid outlet;

end of said treating zone, said closed end being at (g) passing a temperature control medium through said other end of said treating zone, said cylinder said temperature control zone;

substantially encompassing the axially disposed tem- (h) passing said fluid through said axially disposed perature control zone and, in part, by a division of feeding zone into the closed end of said rotating cylsaid annulus, forming and defining with said axially inder;

disposed temperature control zone and with said (i) then passing said fluid through the annulus beside parallel to the axis of said treating zone two tween said rotating cylinder and said axially disposed annuli communicating with each other around the feeding zone;

end of the wall of said cylinder at its open end said (j) then passing said fluid around the said end of the two annuli form a continuous passageway at the end 15 wall of said cylinder through the annulus between of said closed cylinder; said cylinder and said side of said treating zone; and

(e) providing a substantially axial inlet for fluid (k) then removing the thus-agitated and treated fluid through said axially disposed temperature control from said treating zone through said treated fluid zone, into the closed end of said rotating cylinder; outlet at the periphery of said treating zone.

(f) providing a treated fluid outlet from said treating 3. A method according to claim 2 wherein the removal zone approximately at said other end thereof thus of the treated fluid is through a group of outlets subestablishing an unobstructed continuous flow pattern stantially symmetrically disposed peripherally surroundthrough said axial inlet into the closed end of said ing said mounting at said end of said treating zone. cylinder, in said closed end of said cylinder radially 4. A method according to claim 1 wherein the fluid into and then through said annuli and from said being treated is a solution containing at least one montreating zone through said treated fluid outlet; omer and a catalyst adapted to polymerize said monomer:

g) passing a temperature control medium through 5. A method according to claim 1 wherein the fluid each of said temperature control zones; treated is one containing at least one of the following (h) passing said fluid through said axially disposed monomers and polymers:

temperature control zone into the closed end of said bumdiene rotating cylinder; isoprene (i) then passing said fluid through the annulus be- Styrene tween said rotating cylinder and said axially disposed polylbutadiene temperature control zone; ethylene (j) then passing said fluid through the annulus bepropylene tween said cylinder and said treating zone; and

. polyethylene (k) then removing the thus-agitated and treated Polypropylene fluid from said treating zone through said outlet. polyisoprene 2. In a polymerization process, the improved method piperylene for agitating in a unitary operation a viscous, shear-sensi- 4 tive fluid reacting mass, and eflecting improved heat transfer which comprises providing:

(a) a treating zone; (b) an indirectly heat exchanging temperature control zone surrounding said treating zone;

2-methyl-1,3-pentadiene 2-inethyl-5-vinyl pyridine cis-polyisoprene carboxy-telechelic polybutadiene butadiene-styrene block polymer olefin (c) a rotating axially disposed cylindrical agltator diolefisns closed at one end, mounted at said end in said treatpolyolefins ing zone, extending from the mounting at an end of said treating zone substantially toward, but not completely to, the other end of said treating zone and terminating at a substantial distance from said other end of said treating zone;

(d) an axially disposed feeding zone substantially encompassed in said cylindrical and extending into the closed end thereof to feed and to release fluid into the closed end of said cylinder, and, in part, forming and defining with said cylinder and a side of po-lydiolefins (polydienes) alkylstyrene.

6. A method according to claim 1 wherein the fluid being treated contains at least one of a l-olefin and a conjugated diene.

References Cited UNITED STATES PATENTS 2,413,375 12/1946 Pomeroy 259--8 sald treatlng zone, two annuli communicating with each other around the end of the wall of said cyl- 3206287 9/1965 Clawford HOT-949 inder at its open end said two annuli form a continu- (50 FOREIGN PATENTS ous passageway at the end of said closed cylinder; 806,019 12/1958 Great Britain (e) providing a substantially axial inlet for fluid, through said axially disposed feeding zone, to feed fluid into the closed end of said rotating cylinder;

(f) providing a treated fluid outlet from the periphery of said treating zone approximately at said end thereof thus establishing an unobstructed continu- JOSEPH L. SCHOFER, Primary Examiner.

R. A. GAITHER, Assistant Examiner.

US. Cl. X.R. 

1. IN A POLYMERIZATION PROCESS, THE IMPROVED METHOD FOR AGITATING IN A UNITARY OPERATION A VISCOUS, SHEAR-SENSITIVE FLUID REACTING MASS, AND EFFECTING IMPROVED HEAT TRANSFER WHICH COMPRISES PROVIDING: (A) A TREATING ZONE; (B) AN INDIRECTLY HEAT EXCHANGNG TEMPERATURE CONTROL ZONE SURROUNDING SAID TREATING ZONE; (C) AN INDIRECTLY HEAT EXCHANGING TEMPERATURE CONTROL ZONE AXIALLY DISPOSED IN SAID TREATING ZONE, EXTENDING SUBSTANTIALLY INTO SAID TREATING ZONE FROM ONE END THEREOF AND TERMINATING AT A SUBSTANTIAL DISTANCE FROM THE OTHER END THEREOF AND SPACED FROM THE SIDE OF SAID TREATING ZONE PARALLEL TO THE AXIS OF SAID TREATING ZONE, THUS PROVIDING AN ANNULUS; (D) A ROTATING AXIALLY DISPOSED CYLINDRICAL AGITATOR CLOSED AT ONE END, IN SAID TREATING ZONE EXTENDING FROM SAID OTHER END OF SAID TREATING ZONE SUBSTANTIALLY TOWARD SAID ONE END OF SAID TREATING ZONE AND TERMINATING AT A SUBSTANTIAL DISTANCE FROM SAID ONE END OF SAID TREATING ZONE, SAID CLOSED END BEING AT SAID OTHER END OF SAID TREATING ZONE, AND CYLINDER SUBSTANTIALLY ENCOMPASSING THE AXIALLY DISPOSED TEMERATURE CONTROL ZONE AND, IN PART, BY A DIVISION OF SAID ANULUS, FORMING AND DEFINING WITH SAID AXIALLY DISPOSED TEMPERATURE CONTROL ZONE AND WITH SAID SIDE PARALLEL TO THE AXIS OF SAID TREATING ZONE TWO ANNULI COMMUNICATING WITH EACH OTHER AROUND THE END OF THE WALL OF SAID CYLINDER AT ITS OPEN END SAID TWO ANNULI FROM A CONTINUOUS PASSAGEWAY AT THE END OF SAID CLOSED CYLINDERF (E) PROVIDING A SUBSTANTIALLY AXIAL INLET FOR FLUID THROUGH SAID AXIALLY DISPOSED TEMPERATURE CONTROL ZONE, INTO THE CLOSED END OF SAID ROTATING CYLINDER; (F) PROVIDING A TREATED FLUID OUTLET FROM SAID TREATING ZONE APPROXIMATELY AT SAID OTHER END THEREOF THUS ESTABLISHING AN UNOBSTRUCTED CONTINUOUS FLOW PATTERN THROUGH SAID AXIAL INLET INTO THE CLOSED END OF SAID CYLINDER, IN SAID CLOSED END OF SAID CYLINDER RADIALLY INTO AND THEN THROUGH SAID ANNULI AND FROM SAID TREATING ZONE THROUGH SAID TREATED FLUID OUTLET; (G) PASSING A TEMPERATURE CONTROL MEDIUM THROUGH EACH OF SAID TEMPERATURE CONTROL ZONES; (H) PASSING SAID FLUID THROUGH SAID AXIALLY DISPOSED TEMPERATURE CONTROL ZONE INTO THE CLOSED END OF SAID ROTATING CYLINDER; (I) THEN PASSING SAID FLUID THROUGH THE ANNULUS BETWEEN SAID ROTATING CYLINDER AND SAID AXIALLY DISPOSED TEMPERATURE CONTROL ZONE; (J) THEN PASSING SAID FLUID THROUGH THE ANNULUS BETWEEN SAID CYLINDER AND SAID TREATING ZONE; AND (K) THEN REMOVING THE THUS-AGITATED AND TREATED FLUID FROM SAID TREATING ZONE THROUGH SAID OUTLET. 